Automatic drain valve device

ABSTRACT

This invention relates to a drain valve apparatus that includes a manually operative means and an automatically operative means arranged in series with the manual means adjacent a storage reservoir from which each is operative to cause the expulsion of contaminants. The manual means comprises a three-position spherical valve having a passageway extending through its center and a valve seat therefor. This valve seat is formed by two identical members each constituting one-half of a cube that is provided with a hemispherical cavity and four semicircular ports, one located on each side of the member and opening into the hemispherical cavity at the outer periphery thereof. The semicircular ports in the two valve seat members, irrespective of how the two members are arranged one with respect to the other so long as the hemispherical cavities form a spherical cavity for receiving the spherical valve, provide a bearing for receiving a valve stem that is formed integral with the spherical valve to which stem a handle is secured, and a communication through which fluid under pressure and contaminants may be released from the reservoir to atmosphere when the spherical valve is manually rotated by the handle to one of its three positions. When the spherical valve is manually rotated to a second position, it closes the communication to atmosphere and establishes a communication between the reservoir and the automaticallyoperative means. In its third position, the spherical valve closes both of the above-mentioned communications.

United States Patent Wagner 1 Nov. 21, 1972 [54] AUTOMATIC DRAIN VALVEDEVICE includes a manually operative means and an automati- 72 Inventor:Daniel G. Wagner, Pittsburgh, Pa. can) Petative hieahs arranged in twith t manual means adjacent a storage reservoir from which AsslgneeiWestinghouse Brake Company each is operative to cause the expulsion ofcontamiwlimeidmg, nants. The manual means comprises a three-position[22] Filed; March 23, 1970 spherical valve having a passageway extendingthrough its center and a valve seat therefor. This valve PP N05 21,630seat is formed by two identical members each constituting one-half of acube that is provided with a [52] US. Cl. ..137/204, 137/510, 251/75hemispherical cavity and four semicircular P one 51] Int. Cl. ..F16t1/14located err each side of the member and opening into [58] Field ofSearch ..137/204, 203, 510; 251/75 the hemispherical cavity at the outerp p y thereof. The semi-circular ports in the two valve seat [5References Cited members, irrespective of how the two members arearranged one with respect to the other so long as the UNITED STATESPATENTS hemispherical cavities form a spherical cavity for 2,070,4212/1937 Chisholm ..251/75 receiving the spherical valve Pmvide a heating3,516,430 6/1970 Valentine ..137/204 receiving a valve stem that isfumed integral with the 3,472,264 10/1969 Petry ..137/116.5 sphericalvalve to which stem a handle is Secured, and 3,482,591 12/1969 Dufresne..137/1 16.5 e ccmrrihhicetich through which fluid under Pressure2,100,485 11/1937 Lindemann ..137/204 and contaminants may he releasedfrom the reservoir 2,812,860 11/1957 Dilworth ..137/204 x to atmospherewhen the spherical valve is manually 2,730,115 l/1956 Hempel ..137/51024' rotated by the handle to one of its three'pcsitichs- 2,704,5483/1955 Ralston ..137/510 x when the spherical valve is manually rotatedto a Primary ExaminerAlan Cohan Attorney-Ralph W, Mclntire, Jr.

[5 7] ABSTRACT This invention relates to a drain valve apparatus thatilljlllIllli 1;" 2 1 24 "I time. E Y an: I a

second position, it closes the communication to atmosphere andestablishes a communication between the reservoir and theautomatically-operative means. In its third position, the sphericalvalve closes both of the above-mentioned communications.

2 Claims, 2 Drawing Figures PATENTEDnnm I972 3. 703. 1 88 j I INVENTOR.DANIEL G. WAGNER BY W -W MX ATTORNEY AUTOMATIC DRAIN VALVE DEVICEBACKGROUND OF THE INVENTION Drain valve devices heretofore used toeffect the expulsion of contaminants from storage reservoirs have beenof the automatic type operable in response to the pressure in thestorage reservoir reaching a chosen value to release contaminantstherefrom with no means for releasing these contaminants while thepressure in the reservoir is different than this chosen value.

Accordingly, it is the general purpose of this invention to provide anovel, simple and economical combined manually and automaticallyoperable drain valve apparatus for selectively or periodically expellingall contaminants from a storage reservoir.

SUMMARY OF THE INVENTION According to the present invention, a novel,simple and economical manually operated drain valve is disposed in acommunication between a storage reservoir and an automatically operativedrain valve device for at any time, independently of the operation ofthe automatic drain valve device, effecting the expulsion ofcontaminants from the storage reservoir to atmosphere. This manuallyoperated drain valve comprises a spherical valve having a passagewayextending therethrough and two identical members each constitutingone-half of a cube that is provided with a hemispherical cavity andfoursemi-circular ports, one located on each side of the member andopening into the hemispherical cavity at the outer periphery thereof.Irrespective of how the two identical members are arranged one withrespect to the other so long as the two opposed hemispherical cavitiesform a spherical cavity for receiving the spherical valve, two adjacentsemi-circular ports in the two members provide a bearing for receiving avalve stem integral with the spherical valve and two other adjacentsemi-circular ports in these members constitute a communication throughwhich fluid under pressure and contaminants may be released from thereservoir to atmosphere when the spherical valve is manually rotated toone of three positions by a handle secured to the valve stem. Manualrotation of the spherical valve to a second position closes thecommunication to atmosphere and establishes a communication between thereservoir and the automatic drain valve device to enable the periodicalexpulsion of contaminants from the reservoir upon sequential automaticoperation of this automatic drain valve device, and manual rotation ofthe spherical valve to a third position prevents expulsion ofcontaminants from the reservoir and permits removal of certain parts ofthe automatic drain valve device for repairs or replacements.

In the accompanying drawing:

FIG. 1 is a vertical cross-sectional view showing part of a fluidpressure storage reservoir having secured to the bottom thereof acombined manual and an automatically operable drain valve deviceconstructed in accordance with the invention and shown in its closedposition.

FIG. 2 is a cross-sectional view of the automatically operable drainvalve device of FIG. 1 shown in its open or unseated position.

Referring to FIG. 1 of the drawing, the bottom 1 of a fluid pressurestorage reservoir has secured thereto by a pair of cap screws 2 acombined manual and an automatically operative drain valve device 3which is constructed in accordance with the present invention.

The drain valve device 3 comprises a pair of easing sections 4 and 5secured together by a plurality of bolts 6 which extend throughcorresponding smooth bores 7 in the casing section 5 and havescrew-threaded engagement with coaxial bottomed bores 8 provided in thecasing section 4, it being noted that only two of these bolts 6 appearin the drawing.

Formed integral with the casing section 4 is an annu- I lardownwardly-extending lug 9 the end of which is provided with a pluralityof spaced-apart semi-circular recesses 10. Likewise, the casing section5 has formed integral therewith an annular upwardly-extending lug 1 1the upper end of which is spaced from the lower end of the lug 9 adistance equal to the thickness of a diaphragm valve element 12 whichwill now be described in detail.

The valve element 12 comprises an annular Belleville spring 13 having aresilient material such as, for example, rubber bonded to its oppositesides it being noted from the drawing that this resilient materialextends beyond the outer periphery of the Belleville spring 13 to form aflat cylindrical valve element 14 that normally seats against an annularvalve seat 15 that is formed integral with the casing section 4.

As shown in the drawing, the diaphragm valve element 12 cooperates withthe casing sections 4 and 5 to form on its respective opposite sides apressure chamber 16 and a sump chamber 17. It will be noted that thesemi-circular recesses 10 in the annular lug 9 and a plurality ofspaced-apart ports 18 provided in the annular lug 11 provide for theflow of fluid under pressure and the contaminants entrained therein fromthe chamber 16 to the chamber 17 when the flat'cylindrical valve element14 is moved downward and out of seating contact with the annular valveseat 15 upon the pressure in the chamber 16 exceeding the pressure inthe chamber 17.

Formed integral with the resilient material bonded to the lower side ofthe Belleville spring 13 is a poppettype exhaust valve 19 which, whilethe diaphragm valve element 12 occupies the position shown in FIG. I, isseated against a poppet-type exhaust valve seat 20 formed at the upperend of a bore 21 provided in a removable screw-threaded plug 22 that hasscrewthreaded engagement with a screw-threaded bore 23 provided in thecasing section 5.

Formed integral with and of the same resilient material as the exhaustvalve 19 is acylindrical valve stem 24 the diameter of which is lessthan that of the bore 21. This valve stem 24 is moulded to and around ametallic rod 25 disposed therein which rod extends below the end of thestem 24 and, while the exhaust valve 19 is seated on its seat 20, asshown in FIG. 1, to the exterior of the drain valve device 1. By theapplication of a force acting in an upward direction to the lower end ofthe rod 25 while the exhaust valve 19 is seated on its seat 20, as shownin FIG. 1,.this valve 19 can be manually unseated from itsseat 20 andthe Belleville spring 13 simultaneously turned inside out or moved fromthe position shown in FIG. 1 .tothe position shown in FIG. 2 to causethe expulsion. of contaminants contained in the lower part of the sumpchamber 17 to atmosphere via the bore 21 by the fluid under pressuretrapped in the upper part of this chamber'in a manner hereinafterexplained.

As shown in FIG. 1, a flange 26 is integrally connected to the casingsection 4 by a cylindrical neck portion 27. This flange 26 is providedwith a pair of spaced-apart smooth bores 28 and 29 through which thehereinbefore-mentioned cap screws 2 extend and have screw-threadedengagement with coaxial screwthreaded bottomed bores 30 and 31 providedin a pair of spaced-apart bosses 32 and 33 integral with the bottom 1 ofthe storage reservoir.

The flange 26 has a bolting face 35 that abuts the bottom 1 of thestorage reservoir and disposed in an annular groove 36 provided in thisbolting face 35 is a resilient sealing element 37 that forms a seal withthe bottom 1.

As shown in FIG. 1, the casing section 4 is provided with a passageway38 that opens at one end into the chamber 16 and at the opposite endinto a coaxial counterbore 38a that is square in cross section and has adepth equal to the length of one side of the square. The upper end ofthe counterbore 38a opens into a coaxial cylindrical counterbore 39 thediameter of which is substantially greater than the length of the squarecounterbore 38a.

Opening into the square counterbore 38a midway its depth is one end of apassageway 40 that extends through the cylindrical neck portion 27 andopens at its other end at the peripheral surface of the neck portion 27.This other end of this passageway 40 is provided with internal screwthreads for a reason hereinafter made apparent.

Disposed in the bottom of the square counterbore 38a is a member 41 that.constitutes one-half of a cube and has therein a short passageway 42that is coaxial with the above-mentioned passageway 38 in the casing 4.The lower end of this passageway 42 registers with the upper end of thepassageway 38 and the upper end opens into a hemispherical cavity 43provided in the top face of the member 41. Also disposed in the squarecounterbore 38a and in abutting relationship with the member 41 is asecond member 44 that constitutes the other half of the cube and hastherein a short passageway 45 that is coaxial with the passageways 38and 42. The upper end of this passageway 45 opens at the top surface ofthe second member 44 and the lower end opens into a hemispherical cavity46 provided in the bottom face of the member 44.

Each of the members 41 and 44 has four semicircular ports 47, onelocated on each side of the respective member and opening into thecorresponding hemispherical cavity at the outer periphery thereof. Theseports 47 in the two members 41 and 44, irrespective of how these membersare placed in the square counterbore 38a so long as the hemisphericalcavities 43 and 46 form a spherical cavity, provide, first, acommunication between this spherical cavity and the passageway 40, and,second, a bearing for a cylindrical valve stem 48 of a ball-typemanually operated drain valve element 49 disposed in this sphericalcavity.

While the ball-type drain valve element 49 occupies the position shownin FIG. 1, one end of a passageway 50 therein registers with the upperend of the short passageway 42 and the other end opens into a cavity 51that constitutes a spherical sector of the ball-type valve element 49. 1

Disposed in the hereinbefore-mentioned counterbore 39 is an annularmember 52 that is provided with a counter bore 53 for receiving a flange54 that is integral with a screen or strainer device 55 adjacent thelower end thereof, it being noted from FIG. 1 that this strainer device55 extends through a bore 56 provided therefor in the bottom 1 of thestorage reservoir. This strainer device 55 is constructed of screen wireof comparatively large mesh to permit the passage therethrough of waterand particles of small diameter.

The hereinbefore-mentioned cylindrical valve stem 48 extends through abearing formed by two opposed semi-circular ports 47 and a bore (notshown) in neck portion 27 and is provided with a short extension 57 thatissqu are in cross section. This short extension 57 extends through acorresponding square hole in a bandle 58this handle being retained onthe extension 57 by any suitable means (not shown).

By manually rotating the handle 58 from the position shown in FIG. 1clockwise through an angle of 45, the ball-type valve element 49 isrotated from the position shown in FIG. 1 to a second or manual drainposition in which water, moisture and contaminants of reasonable smallsize in the bottom of the storage reservoir may flow to atmosphere viathe strainer device 55, short passageway 45, cavity 51 in valve element49, the port provided by two opposed semi-circular ports 47 andpassageway 40. If desired, a threaded end of a piece of pipe can bescrew-threaded into the internal screw threads in the passageway 40 toconvey this water, moisture and contaminants to a location where theywill not fall or be deposited on top of the casing section 4 whendischarged to atmosphere from the end of this pipe.

By manual rotation of the handle 58 from the position shown in FIG. 1clockwise through an angle of the ball-type valve element 49 is rotatedfrom the position shown in FIG. 1 to a third position in which theinterior of the storage reservoir is cut off from both the automaticallyoperative drain valve device 3 and the passageway 40 and pipe connectedthereto to permit removal of easing 5 and diaphragm valve element 12subsequent to the withdrawal of bolts 6 from bottomed bores 8.

For the purpose of understanding the operation of the invention, it willsuffice to state that a compressor (not shown) together with an unloader(not shown) and a governor (not shown) function in the usual wellknownmanner tomaintain pressurized fluid in the storage reservoir within anoperating range between a predetermined minimum and maximum pressure.When the compressor is unloaded, it operates without compressing furtherfluid under pressure into the storage reservoir.

Referring to FIG. 1, it will be seen that fluid under pressure will flowfrom the storage reservoir to the chamber 16 in the drain valve device 3via the strainer device 55, short passageway 45, cavity 51 andpassageway 50 in the ball-type valve element 49, short passageway 42 andpassageway 38. It will be noted that water, moisture and any othercontaminants entrained in the fluid under pressure in the storagereservoir that are small enough to pass through the strainer device 55will flow to the chamber 16 along with the fluid under pressure, itbeing remembered that this strainer device 55 is constructed of screenwire of comparatively large mesh.

Fluid under pressure and the contaminants entrained therein that aresupplied to the chamber 16 will flow through the plurality ofsemi-circular recesses in the annular lug 9 and act in a downwarddirection on top of the flat cylindrical valve element 14 extendingbeyond the outer periphery of the Belleville spring 13 and constructedof a resilient material to unseat this valve element 14 from the annularvalve seat 15. When the valve element 14 is thus unseated from valveseat 15, fluid under pressure and the contaminants entrained thereinflows past this unseated valve element 14 and to the chamber 17 via theplurality of ports 18 in the annular lug 11. Thus, the pressure in thechambers 16 and 17 is increased simultaneously as the compressorincreases the pressure in the storage reservoir until the governoroperates to unload the compressor.

It will be understood that the contaminants entrained in the fluid underpressure supplied to the chamber 17 will settle to the bottom of thischamber and be subjectcd to the fluid under pressure present thereinwhich fluid under pressure is confined to the remaining volume of thischamber that is above these contaminants and below the valve element 12subsequent to the seating of the valve element 14 on the seat 15 whichoccurs upon unloading of the compressor.

Subsequent to the unloading of the compressor, the usage of fluid underpressure from the storage reservoir will effect a reduction of thepressure therein. Since the chamber 16 in the drain valve device 3 isdirectly connected to the storage reservoir via passageways 38, 42 and50, cavity 51, short passageway 45 and strainer device 55, acorresponding reduction of pressure will occur in the chamber 16, itbeing understood that the cylindrical valve element 14 is seated on thevalve seat 15 and therefore, prevents a corresponding reduction ofpressure in the chamber 17.

It is a known characteristic of Belleville springs that if the ratio ofheight to thickness is greater than 1.41, the load reaches a peak andthen decreases with further deflection. If the ratio of height tothickness is greater than 2.83, the load will become negative at somepoint beyond the horizontal position and will require loading in theopposite direction to bring it back to its free position. In otherwords, it will turn inside out. For a constant load spring the ratio ofheight to thickness should be between 1.3 and 1.6.

In order to insure proper operation of the drain valve 3, the ratio ofheight to thickness of the Belleville spring 13 should be between 1.6and 2.83 so that this spring will turn inside out upon the pressure inthe chamber 16 being reduced to a value that is a chosen amount less,for example, 10 pounds per square inch, than the pressure trapped in thechamber 17 by the valve 14, and then return to the position shown inFIG. 1 upon the pressure in the chamber 17 being reduced to a chosenvalue, which, for example, may be 132 pounds per square inch.

Assuming that the governor operates to effect unloading of thecompressor upon the pressure in the storage reservoir 1 reaching a valueof, for example, 140 pounds per square inch, it will be understood thatthe pressure in the chambers 16 and 17 in the drain valve device 3 isthe same as that in the storage reservoir prior to use of compressedfluid from this reservoir. Accordingly, when the use of fluid underpressure from the storage reservoir has reduced the pressure therein andin the chamber 16 in drain valve device 3 to a value of pounds persquare inch, it being remembered that the trapped pressure in thechamber 17 is pounds per square inch, a pressure differential of 10pounds per square inch is established on the opposite sides of thediaphragm valve element 12 and likewise on the opposite sides of theBelleville spring 13 which differential is acting in an upward directionand is sufficient to cause this Belleville spring to turn inside out.

When the Belleville spring 13 is thus turned inside out, or moved fromthe position in which it is shown in FIG. 1 to the position in which itis shown in FIG. 2, the diaphragm valve element 12 and exhaust valve 19are likewise moved to the position shown in FIG. 2 in which the exhaustvalve 19 is unseated from its seat 20 and the stem 24 and rod 25withdrawn from the bore 21.

When the valve 19 is thus unseated from its seat 20, the trapped fluidunder pressure present in the chamber 17 above the contaminants in thischamber and acting on the lower side of the valve element 12 is renderedeffective to force substantially all of the contaminants in the chamber17 to flow to'atmosphere via the bore 21 before this fluid underpressure likewise flows to atmosphere via this bore.

When the fluid under pressure present in the chamber 17 has reduced to avalue of, for example, 132 pounds per square inch, the remainingdifferential fluid pressure force acting on the opposite sides of theBelleville spring 13 is insufficient to maintain this spring turnedinside out and in the position in which it is shown in FIG. 2.

Consequently, it turns outside in or, in other words, returns or snapsback to the position shown in FIG. 1.

When the Belleville spring 13 returns to the position shown in FIG. 1,it is effective to simultaneously deflect the diaphragm valve 12downward to the position shown in FIG. 1. In this position of thediaphragm valve 12 and Belleville spring 13, this spring is effective tobias the exhaust valve 19 against its seat 20 which prevents furtherflow of fluid under pressure from the sump chamber 17 to atmosphere viathe bore 21 in which is now disposed the valve stem 24.

When further use of fluid under pressure from the storage reservoirreduces the pressure therein to the value at which the governor operatesto reload the compressor, this compressor will operate to supply fluidunder pressure to the storage reservoir and to the chambers 16 and 17 inthe drain valve device 3 until the pressure therein is increased to thevalue required to cause unloading of the compressor.

Subsequent use of fluid under pressure from the storage reservoir willreduce the pressure therein and in the chamber 16 to cause the drainvalve device 3 to again operate in the manner hereinbefore described indetail to release contaminants from the chamber 17 in the drain valvedevice 3.

From the foregoing, it is apparent that each time the pressure in thestorage reservoir is reduced a certain amount as the result of usage offluid under pressure therefrom subsequent to the unloading of thecompressor that supplies fluid under pressure to this storage reservoir,the drain valve device 3 operates to expel contaminants to atmosphere.Thus, the storage reservoir is kept substantially free of contaminantswhich if allowed to collect therein would reduce its volume andtherefore, the quantity of fluid under pressure stored therein.

Having now described the invention, what I claim as new and desire tosecure by Letters Patent, is:

1. Apparatus operable in response to a certain degree of reduction ofpressure in a fluid pressure storage reservoir to expel contaminantstherefrom, said apparatus comprising, in combination: I

a. a two-position snap-acting Belleville spring normally subject on itsrespective opposite sides to a fluid pressure force in accordance withthe pressure of fluid present in the storage reservoir and operable tosnap respectively from one to another position and from said anotherposition to said one position accordingly as the fluid pressure forceeffective on one side is respectively decreased and subsequentlyincreased with respect to the fluid pressure force on the other side,

b. an abutment having a pair of separate fluid pressure chambers at therespective opposite sides thereof and so cooperating with saidBelleville spring that the pressure in one of said chambers is effectiveon said one side of said spring and the pressure in the other of saidchambers is effective on said other side of said spring,

c. means effective to supply fluid under pressure from the fluidpressure storage reservoir to each of said chambers, the contaminantsentrained in said fluid under pressure being supplied therewith to atleast said other chamber, and said one chamber being constantly incommunication with the fluid pressure storage reservoir,

d. an exhaust valve operated by said abutment to establish a fluidpressure communication between said other chamber and atmosphere throughwhich contaminants and fluid under pressure are successively releasedfrom said other chamber to atmosphere in response to a reduction of thepressure in said one chamber and correspondingly the fluid pressureforce on said one side of said spring as the result of usage of fluidunder pressure from thefluid pressure storage reservoir sufficient tocause the establishment of that differential fluid pressure force onsaid spring required to effect the snap action thereof necessary toenable said abutment to operate said exhaust valve to establish saidfluid pressure communication, said exhaust valve being operable by saidabutment to close said fluid pressure communication in response to areduction of the pressure in said other chamber and correspondingly thefluid pressure force on said other side of said spring sufficient tocause the establishment of that differential fluid pressure force onsaid spring required to effect the snap action thereof necessary toenable said abutment to operate said exhaust valve to close said fluidpressure communication, e. a removable exhaust valve seat for saidexhaust valve, and wherein the improvement comprises f. a three-positionmanually-operable drain valve interposed between the interior of thestorage reservoir and said one chamber and comprising: i. a sphericalvalve element having an operating stem and rotatable by said stem to afirst, a second and a third position, said valve element having apassageway extending through the center of said element, one end of saidpassageway opening at the surface of said spherical valve element andthe other end opening into a cavity that constitutes a spherical sectorof said spherical valve element,

a valve seat for said spherical valve element, said valve seatcomprising: l. a pair of valve seat members each of which constitutesone-half of a cube and is provided with a hemispherical cavity and foursemi-circular ports, one located on each side of said valve seat memberand opening into the corresponding hemispherical cavity at the outerperiphery thereof, said semi-circular ports in said pair of valve seatmembers, irrespective of how said members are arranged one with respectto the other so long as said hemispherical cavities form a sphericalcavity for receiving said spherical valve element, providing a bearingfor receiving said valve stem and a communication through which fluidunder pressure and contaminants may be released from the interior of thestorage reservoir to atmosphere in said second position of saidspherical valve element, and iii. a handle secured to said operatingstem for effecting manual rotation of said spherical element to its saidpositions, in the first of which it establishes a first communicationbetween the storage reservoir and said one chamber, in the second ofwhich it closes said first communication and establishes a secondcommunication between the interior of the storage reservoir andatmosphere, and in the third of which it closes said first and secondcommunications.

2. Apparatus to expel contaminants from a fluid pressure storagereservoir, as'recited in claim 1, further characterized in that saidapparatus further comprises a sectionalized casing having a pair ofopposed cupshaped casing sections each of which has an annularperforated lug integral with and extending from the bottom thereofbetween which lugs said abutment is anchored, said cup-shaped casingsections cooperating with said abutment to form on the respectiveopposite sides thereof said one and said other chamber into each ofwhich one of said lugs extends, one of said casing sections beingprovided with a flange having a bolting face to enable said apparatus tobe removably secured to a corresponding bolting face on the storagereservoir and with a square counterbore extending inward from saidbolting face of said flange to a depth sufficient to provide a cubicalcavity for receiving said pair of valve seat members.

1. a pair of valve seat members each of which constitutes one-half of acube and is provided with a hemispherical cavity and four semi-circularports, one located on each side of said valve seat member and openinginto the corresponding hemispherical cavity at the outer peripherythereof, said semi-circular ports in said pair of valve seat members,irrespective of how said members are arranged one with respect to theother so long as said hemispherical cavities form a spherical cavity forreceiving said spherical valve element, providing a bearing forreceiving said valve stem and a communication through which fluid underpressure and contaminants may be released from the interior of thestorage reservoir to atmosphere in said second position of saidspherical valve element, and iii. a handle secured to said operatingstem for effecting manual rotation of said spherical element to its saidpositions, in the first of which it establishes a first communicationbetween the storage reservoir and said one chamber, in the second ofwhich it closes said first communication and establishes a secondcommunication between the interior of the storage reservoir andatmosphere, and in the third of which it closes said first and secondcommunications.
 1. Apparatus operable in response to a certain degree ofreduction of pressure in a fluid pressure storage reservoir to expelcontaminants therefrom, said apparatus comprising, in combination: a. atwo-position snap-acting Belleville spring normally subject on itsrespective opposite sides to a fluid pressure force in accordance withthe pressure of fluid present in the storage reservoir and operable tosnap respectively from one to another position and from said anotherposition to said one position accordingly as the fluid pressure forceeffective on one side is respectively decreased and subsequentlyincreased with respect to the fluid pressure force on the other side, b.an abutment having a pair of separate fluid pressure chambers at therespective opposite sides thereof and so cooperating with saidBelleville spring that the pressure in one of said chambers is effectiveon said one side of said spring and the pressure in the other of saidchambers is effective on said other side of said spring, c. meanseffective to supply fluid under pressure from the fluid pressure storagereservoir to each of said chambers, the contaminants entrained in saidfluid under pressure being supplied therewith to at least said otherchamber, and said one chamber being constantly in communication wiTh thefluid pressure storage reservoir, d. an exhaust valve operated by saidabutment to establish a fluid pressure communication between said otherchamber and atmosphere through which contaminants and fluid underpressure are successively released from said other chamber to atmospherein response to a reduction of the pressure in said one chamber andcorrespondingly the fluid pressure force on said one side of said springas the result of usage of fluid under pressure from the fluid pressurestorage reservoir sufficient to cause the establishment of thatdifferential fluid pressure force on said spring required to effect thesnap action thereof necessary to enable said abutment to operate saidexhaust valve to establish said fluid pressure communication, saidexhaust valve being operable by said abutment to close said fluidpressure communication in response to a reduction of the pressure insaid other chamber and correspondingly the fluid pressure force on saidother side of said spring sufficient to cause the establishment of thatdifferential fluid pressure force on said spring required to effect thesnap action thereof necessary to enable said abutment to operate saidexhaust valve to close said fluid pressure communication, e. a removableexhaust valve seat for said exhaust valve, and wherein the improvementcomprises f. a three-position manually-operable drain valve interposedbetween the interior of the storage reservoir and said one chamber andcomprising: i. a spherical valve element having an operating stem androtatable by said stem to a first, a second and a third position, saidvalve element having a passageway extending through the center of saidelement, one end of said passageway opening at the surface of saidspherical valve element and the other end opening into a cavity thatconstitutes a spherical sector of said spherical valve element, ii. avalve seat for said spherical valve element, said valve seatcomprising:
 1. Apparatus operable in response to a certain degree ofreduction of pressure in a fluid pressure storage reservoir to expelcontaminants therefrom, said apparatus comprising, in combination: a. atwo-position snap-acting Belleville spring normally subject on itsrespective opposite sides to a fluid pressure force in accordance withthe pressure of fluid present in the storage reservoir and operable tosnap respectively from one to another position and from said anotherposition to said one position accordingly as the fluid pressure forceeffective on one side is respectively decreased and subsequentlyincreased with respect to the fluid pressure force on the other side, b.an abutment having a pair of separate fluid pressure chambers at therespective opposite sides thereof and so cooperating with saidBelleville spring that the pressure in one of said chambers is effectiveon said one side of said spring and the pressure in the other of saidchambers is effective on said other side of said spring, c. meanseffective to supply fluid under pressure from the fluid pressure storagereservoir to each of said chambers, the contaminants entrained in saidfluid under pressure being supplied therewith to at least said otherchamber, and said one chamber being constantly in communication wiTh thefluid pressure storage reservoir, d. an exhaust valve operated by saidabutment to establish a fluid pressure communication between said otherchamber and atmosphere through which contaminants and fluid underpressure are successively released from said other chamber to atmospherein response to a reduction of the pressure in said one chamber andcorrespondingly the fluid pressure force on said one side of said springas the result of usage of fluid under pressure from the fluid pressurestorage reservoir sufficient to cause the establishment of thatdifferential fluid pressure force on said spring required to effect thesnap action thereof necessary to enable said abutment to operate saidexhaust valve to establish said fluid pressure communication, saidexhaust valve being operable by said abutment to close said fluidpressure communication in response to a reduction of the pressure insaid other chamber and correspondingly the fluid pressure force on saidother side of said spring sufficient to cause the establishment of thatdifferential fluid pressure force on said spring required to effect thesnap action thereof necessary to enable said abutment to operate saidexhaust valve to close said fluid pressure communication, e. a removableexhaust valve seat for said exhaust valve, and wherein the improvementcomprises f. a three-position manually-operable drain valve interposedbetween the interior of the storage reservoir and said one chamber andcomprising: i. a spherical valve element having an operating stem androtatable by said stem to a first, a second and a third position, saidvalve element having a passageway extending through the center of saidelement, one end of said passageway opening at the surface of saidspherical valve element and the other end opening into a cavity thatconstitutes a spherical sector of said spherical valve element, ii. avalve seat for said spherical valve element, said valve seatcomprising:
 1. a pair of valve seat members each of which constitutesonehalf of a cube and is provided with a hemispherical cavity and foursemi-circular ports, one located on each side of said valve seat memberand opening into the corresponding hemispherical cavity at the outerperiphery thereof, said semi-circular ports in said pair of valve seatmembers, irrespective of how said members are arranged one with respectto the other so long as said hemispherical cavities form a sphericalcavity for receiving said spherical valve element, providing a bearingfor receiving said valve stem and a communication through which fluidunder pressure and contaminants may be released from the interior of thestorage reservoir to atmosphere in said second position of saidspherical valve element, and iii. a handle secured to said operatingstem for effecting manual rotation of said spherical element to its saidpositions, in the first of which it establishes a first communicationbetween the storage reservoir and said one chamber, in the second ofwhich it closes said first communication and establishes a secondcommunication between the interior of the storage reservoir andatmosphere, and in the third of which it closes said first and secondcommunications.